1. Field of the Invention
The present invention relates to an iron golf club having a balance weight provided on a rear face of a head body thereof.
2. Description of the Related Art
Golf clubs which comprise a head and a shaft, are generally classified as one of three types: a wood, an iron, or a putter. Irons are classified by the loft angle of their head. Irons with a small loft angle (for example, from 20 to 30 degrees) are called "long irons", while irons with a large loft angle (for example, from 40 to 50 degrees) are called "short irons". Normally, irons are numbered in ascending order from longest to shortest, for example, Nos. 1, 2, 3, 4, 5, 6, 7, 8, 9 and PW (pitching wedge).
The head of an iron club may have a concave back (a cavity-back iron) on the rear of the face which is the front of the head for hitting golf balls, or may have a smooth back (a solid-back iron). The front has an area known by such names as "the sweet spot".
It is widely recognized that to enlarge such sweet spot, the center of gravity of the head may be positioned as rearwardly as possible. In Japanese Patent Un-Examined Publication No.7-59883, which was filed by the same assignee as that of the present application, is proposed a means for providing a club head with such rearwardly positioned center of gravity, in which the rear face of the head body is formed with a cavity, into which is securely fitted a balance weight. Further, in Japanese Utility Model Examined Publication No.53-288 is taught a golf club which is provided with a plurality of balance weights along a peripheral edge of a rear face of a head.
The head disclosed in the Publication No.7-59883 has a single balance weight only, so that there is a limit in adjusting the position of the center of gravity of the head or the head balance. On the other hand, the head disclosed in the Publication No.53-288 is provided with a plurality of balance weights, and thus the degree of freedom in doing so is able to be improved.
Whereas, as the Publication No.53-288 proposes that the balance weights are biasedly arranged, the fine adjustment of the weight balance and/or moment of inertia of the head required for respective club heads such as for the 1st iron or for the 2nd iron, would be impossible.